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(No Model.)

J. W. GILBERT. DENTAL ENGINE HANDPIBOB.

Patented Mar. 29, 1898.

/VE TOR WITNESSES:

mi: Non'ms PETERS co.. Pnoauwa., wAsremuYoN. n. c.

UNrrnn STATES Arnr Finca.

JOI-IN W. GILBERT, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO THE S. S.WHITE DENTAL MANUFACTURING COMPANY, OF SAME PLACE.

DENTAL-ENGINEWHANDPIECE.

SPECIFICATION forming part of Letters Patent No. 601,395,vdated March29, 1898.

Application iiled October 2,1897.

To all whom, t may con/cern:

Beit known that I, JOHN W. GILBERT, a citizen of the United States,residing at Philadelphia, in the county of Philadelphia and State ofPennsylvania, have invented a certain new and useful Improvement inDental- Engine Handpieces; and I do hereby declare the following to be afull, clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame.

My invention relates to a certain improvenient, as hereinafter claimed,in dental-en gine handpieces of the class known as chuckhandpieces; andmy object chiefly is to improve that type of this class of haudpiecesshown in Letters Patent of the United States' No. 291,571, dated JanuaryS, 1884.

In the accompanying drawings, Figure l is a viewin elevation of a handpiece with myimprovement applied thereto. Fig. 2 is a longitudinalcentral section, on an enlarged scale, of the handpiece shown in Fig. 1.Fig. 3 is a cross-section on the line 3 3 of Fig. 2. Fig. i is a View inelevation of the front reduced tubular portion of the telescopic sectionof the handpiece detached. Fig. 5 is a perspective view of theadjustable bearing or chuck for clamping the movable sections of thehandpiece together, and Fig. 6 is an end view of the nut or collar foroperating said adjustable bearing or chuck.

The handpiece'shown in the patent above referred to and to which myimprovement is shown as applied consists, essentially, of ahandle-section A and a telescopic or sliding section C, havingtelescoping or sliding connection with the handle-section by wayof atubular union-piece B, detachably connected with the handle-section, thefront reduced tubular portion C of the telescopic section being adaptedto slide in the tubular unionpiece. A tubular spindle D is fitted toturn in the handle-section A, and a tubular split endwise-movabletool-holding chuck E is fitted within the front end of the tubularspindle. Apivoted lever F is also mounted in the tubular spindle andbears upon a headed Y pin f, which enters and bears upon a section F ofthe chuck. VMovable endwise with and turning independently of thetelescopic sec- Serial No. 653,804. (No model.)

tion O is a driving-shaft G, provided with a serrated wedge or inclinedsurface g on its forward end, which enters and is adapted to slide inthe tubular spindle and bear upon the long arm of the lever F.

Vithout further description of the construction of the handpiece theoperation will readily be understood. YWhen the telescopic section ispulled rearwardly the driving-shaft G is also moved rearwardly and thewedge thereon rocks the lever F and forces the toollocking chuckforward, thus compressing its jaws and locking the shank of a tool .Iinserted therein. Upon pushing the handle andtelescopic sectionstogether the pressure on the chuck is relieved and the tool released.

The sliding or telescopic connection between the handle-section and thetelescopic section after long use of the handpiece sometimes wears andpermits of an undesirable looseness of the parts. In order to overcomethisobjection, I have provided means for inaking a tight connectionbetween the handlesection and the telescopic section, or, in otherwords, I have provided an adjustable bearing or chuck for the slidingconnection between the two sections ofthe handpiece. To

this end the bore of the-union-piece of the handle-section is enlargedfor a portion of its length, so as to provide a seat for anadjustable-bearing, shown in this instance as consistin g of a splitchuck I-I. This chuck, which is tubular and surrounds the front reducedportion of the telescopic section, is beveled on its opposite ends. Oneof these beveled ends bears against the correspondingly-beveled lowerend of a seat in the union-piece, while the opposite beveled end isadapted to be borne upon by an interiorly-threaded collar or nut I,screwing upon the eXteriorlythreaded endy of the union-piece. The collaror nut I is provided with a spline or feather t', adapted to engage alongitudinal groove c in the telescopic section, so that said sectionmay slide freely through the collar or nut andv the section and nut beturned together. By this means the collar or nut may be turned inopposite directions by the turning of the telescopic section of thehandpiece and caused to screw backward or forward upon the unionpiece,according to the direction in which it roo is turned. When the nut isturned in one directionsay to the right-it forces the chuck forward andcaus'esits opposite split ends to bear upon and grip the telescopicsection, whereby any looseness between the sliding sections of thchandpiece may be taken up and the telescopic sectionv locked in order toprevent its being accidentally pushed for# Ward relatively to thehandle-section.

The operation of my improved handpiece is as follows: When the handpieceis adjusted, as shown in Fig. 2,with the sections pushed together, theshank of a tool, as J, may be inserted in the toolholding chuck E andfirmly clamped therein by pulling the telescopic section rearwardly, asshown in Fig. 1. By turning the'telescopicsection to the rightrelatively to the handle-section the telescopic section may be clampedin the handle-section, as before explained. To unlock the tool, it isonly necessary to turn the telescopic section slightly to the left torelease it from the grip of the adjustable bearing or chuck andthen'push it forward to unlock the tool-chuck.

.It will be observed that it is not necessary to clamp the telescopicsection with any considerable force, a very slight^turn of the nut Iusually being all that is needed; but the telescopic section may befirmly clamped and locked, if desired.

I do not wish to be understood as confining myinven tion to the preciseform of adjustable bearing or chuck shown and described or to theparticular style of handpiece to which my improvement is shown asapplied, as any suitable form of adjustable bearing or chuck may beemployed, and the improvement is applicable to any style of handpiece ofthe class employing telescopic mechanism for operating the tool-holdingchuck. The means shown for operating the adjustable bearing or chuck mayalso be varied without departing from the spirit of my invention, and,if desired, it may be operated directly by the fingers instead ofthrough the telescopic section. Instead of the split-ended metal chuck Imay use a tubular packing, as of leather or other yielding material,which may be caused to frictionally bear upon .the telescopic sectionand vact as an adjustable bearing or packing therefor.

I claim as my invention l. The combination, in a Vdental-enginehandpiece, 0f the handle-section, the telescopic section, the adjustablebearing for clamping the two sections together, and the connections foractuating the adjustable bearing by the telescopic section,substantially as set forth.

2. The combination, in a dental-engine handpiece, of the handle-section,the telescopic section, the tubular spindle in the handle-section, thetool-locking chuck in said tubular spindle, means actuated by theendwise movement of the telescopic section for locking and unlocking thetool-locking chuck, and the adjustable bearing for clamping thetelescopic section to the handle-section, substantially as described.

3. The combination, in a dental-engine handpiece, of the handle-section,the telescopic section having slidingV or telescopic connection with thehandle-section, the adj ustable bearing carried by the handle-sectionand adapted to frictionally clamp the telescopic section, and the nut orcollar actuated by the telescopic section for operating said adjustablebearing, substantially as set forth. In testimony whereof I affix mysignature in presence of two witnesses.

J OI-IN W. GILBERT.

Witnesses: y

GEO. W. CLEMENT, HARRY R. BARBER.

